Rotary expansion motor



A ril 18, 196 o. J. KING ETAL ROTARY EXPANSION MOTOR 4 Sheets-Sheet 1 Filed Dec. 27, 1965 IIII INVENTORS o. J. KING RAY E. HUDSON ATTORNEYS l 18, 1957 I o. J. KING ETAL 3,314,333

ROTARY EXPANS ION MOTOR Filed D80. 27, 1965 4 Sheets-Sheet 2 INVENTORS O. J- KING RAY E. HUDSON ATTORNEYS April 18, 1967 o. J. KING ETAL 3,314,333

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ROTARY EXPANSION MOTOR Filed Dec. 27, 1965 4 Sheets-Sheet 4.

INVENTORS O.J. G

RAY UDSON WWW v ATTORNEYS United States Patent 3,314,333 ROTARY EXPANSION MOTOR 0. J. King and Ray E. Hudson, both of Odessa, Tex., as-

signors to Basin Recovery Corporation, Midland, Tex., a corporation of Texas Filed Dec. 27, 1965, Ser. No. 516,601 4 Claims. (Cl. 91-129) The present application relates to a rotary expansion motor, particularly an expansion motor used in the ex traction of gasoline from small natural gas sources.

Applicants have developed a rotary expansion motor including an expansion chamber permitting efiicient expanding of the natural gas to a lower pressure and obtaining significant temperature drops. The motor involves an expansion chamber progressively expanding from the gas inlet port to the gas outlet port and an eccentrically mounted rotor having radially outwardly extending vanes, resiliently urged against the walls of the expansion chamber so as to obtain a complete seal. The shaft of the rotor may be coupled to a drive shaft or any power absorbing device for braking or driving in a bootstrap operation.

Accordingly, it is an object of invention to provide a rotary expansion motor for efficient operation in relatively low production natural gas formations.

Another object of invention is to provide an economical and easily serviced expansion motor permitting natural gas expansion within the approximate range 1-2 to 1-5.

Yet another object of invention is to provide a rotary expansion motor for economical operation in natural gas formations which cannot be economically worked with conventional expansion equipment.

Yet, additional objects of invention will become apparent from the ensuing specification and attached drawings, wherein:

FIG. 1 is a side elevation of the expansion chamber housing, showing the open gas inlet port 26 and the gas outlet port 28;

FIG. 2 is a vertical section of the housing, showing the mounting of the rotor and radially extending vanes 68, 70 within the expansion chamber;

FIG. 3 is a transverse section thereof, showing the leaf spring means 64 urging the radially extending vanes to various degrees of extension;

FIG. 4 is a fragmentary perspective, showing the engagement of the vane tips with respect to the gas expansion chamber 30; and

FIG. 5 is a fragmentary section showing a modification, wherein the vane tip portion is inwardly inclined as at 8 6 and one or more longitudinal grooves 87 may be employed to enable gas pressurization.

In FIG. 1 rota-ry expansion housing 10 is designated as having opposed end plates 12 and 14 secured by bolts and opposed end caps 16 and 18 secured in turn by bolts 20. Rotor shaft extension 22 is illustrated in fragment as protruding from the housing through hub 24. Gas inlet port 26 is shown as including cut-off point 32 and a portion of the expansion chamber is shown. Open gas outlet port 28 is shown also, together with the expansion chamber end. Optional lubrication feed points 38 and 40 are also shown. However, it is anticipated that the device can be operated without lubricants.

FIG. 2 contains additional detail, showing the rotor shaft 42 mounted by means of angular contact duplex ball bearings 50. Bearing lubricant is isolated by mechanical seals 43 within oil reservoir 48, connected to filling channel 44 illustrated in phantom. Lock nut and lip seal wear ring 52 is operated with a lip seal 54.

As illustrated particularly in FIGS. 2 and 3, rotor 42 has a plurality of radially extending vanes 68, 70, 72, 73, 76, 78, S0 and 82. Each vane may abut at its foot Patented Apr. 18, 1967 'ice respective push rods 56, 58, 60, -62, which extend diametrically through shaft and rotor 42 and urged the respective vanes radially outwardly of the rotor periphery by means of leaf or bow springs 64. As a result, the vane outer ends or tips are at all times engaging the walls of expansion chamber 30 or a foraminous grill extension 36. Thus, the vanes are inwardly pushed by the walls of the housing between exhaust port 28 and gas inlet port 26, before cut-oif point 32 where the input gas is received. Thereafter, the vanes are gradually radially outwardly extended within crescent-shaped expansion chamber 30, returning inwardly as the expanded gas is delivered to exhaust chamber 64. It is not necessary that springs 64 be used, for as will be apparent, the engagement of the vane ends with the walls of expansion chamber 30 and grill extension 36 urges the individual vane ends radially inwardly. Pressure equalization channels 84 may extend rearwardly of each vane from the periphery of the rotor to the leaf spring area beneath each vane. Alternatively, according to the modification shown in FIG. 5, pressure equalization channel 84 may be eliminated and the top rear portion of the individual vane tips may be rearwa-rdly inclined inwardly as at 86 and the aft side of the vanes grooved, as shown in phantom.

As will be apparent, the rotor shaft extension 2-2 may be utilized to drive another compressor in a bootstrap operation or may be attached to a braking device to regulate the flow of gas. Normally, cut-oft point 32 is machined to the characteristics of each natural gas formation so as to provide the desired expansion ratio. It is anticipated that the device will be particularly useful in well formations producing 500,000 standard cubic feet per day or less at variant pressures. For example, in one installation where natural gas at 25 gauge 40 absolute was expanded to atmospheric pressure, there was achieved a 61 temperature drop. This cooling effect can be utilized, of course, to recover the hydrocarbons in the natural gas. In addition to machining cut-off point 32 for the desired expansion ratio range in the proposed range 1-2 to 1-5, contnols may consist in varying the bypass around the compressor in a bootstrap operation and varying the braking which may be applied to shaft extension 22. Mechanical seals 43 can be employed to isolate the lubrication system for the bearings from the natural gas stream passing through the engine. Normally, the lubrication system is required to be isolated from the natural gas to prevent absorption of lubrication by natural gas. The output bearing lock nut and lip seal wearing 54 can be readily replaced.

Manifestly, the width of the vanes can be changed to suit the characteristics of any particular job. For example, in a 580,000 s.c.f. per day production vanes of a 10 width were employed, the motor rotating at an average speed of 1,000 rpm. In a 352,000 s.c.f. per day production 10 vanes were also employed to achieve a 60 F. temperature reduction, the rotor rotating at an average of 600 r.p.m.

The device may be used also, for producing power from the natural gas stream, however, expansion for refrigeration purposes is the basic aim of the invention. As will be apparent, the device is capable of being driven in the opposite direction, that is clockwise to serve as a compressor.

Manifestly, various changes in structure, including means of tensioning the vanes and configuring the expansion chamber, may be employed without departing from the spirit and scope of invention, as define-d in the sub-joined claims.

We claim:

1. A rotary expansion motor of the type used in extraction'of gasoline from small natural gas sources comprising:

(A) a housing enclosing a progressively expanding chamber, having (i)' a gas inlet port mounted at the smaller end of said chamber, and (ii) a gas outlet port mounted at the larger end of said chamber;

(B) an eccentrically mounted rotor supported upon a shaft within said chamber and having radially extending blades, resiliently urged outwardly against the walls of said expansion chamber, and

(C) a foraminous grill supported within said chamber, so as to limit radial extension of said vanes during rotation across said inlet port and across said exhaust port.

2. A rotary expansion motor as in claim 1, wherein said progressively expanding chamber is crescent-shaped in side elevation and in front elevation has a narrower width than said vanes.

3. A rotary expansion motor as in claim 1, wherein the combination of eccentric mounting of said rotor and said foraminous grill urge said rotor blades radially inwardly from the exhaust point to the point of gas inlet, while permitting radial outward extension of said blades References Cited by the Examiner UNITED STATES PATENTS 2,426,491 8/1947 Dillon l03136 2,717,770 9/1955 Gibson et al 103-136 3,000,324 9/1961 Rosaen 103136 3,036,527 5/1962 Peterson 103136 DONLEY J. STOCKING, Primary Examiner.

MARK NEWMAN, Examiner. R. M. VARGO, W. J. GOODLIN, Assistant Examiners. 

1. A ROTARY EXPANSION MOTOR OF THE TYPE USED IN EXTRACTION OF GASOLINE FROM SMALL NATURAL GAS SOURCES COMPRISING: (A) A HOUSING ENCLOSING A PROGRESSIVELY EXPANDING CHAMBER, HAVING (I) A GAS INLET PORT MOUNTED AT THE SMALLER END OF SAID CHAMBER, AND (II) A GAS OUTLET PORT MOUNTED AT THE LARGER END OF SAID CHAMBER; (B) AN ECCENTRICALLY MOUNTED ROTOR SUPPORTED UPON A SHAFT WITHIN SAID CHAMBER AND HAVING RADIALLY EXTENDING BLADES, RESILIENTLY URGED OUTWARDLY AGAINST THE WALLS OF SAID EXPANSION CHAMBER, AND (C) A FORAMINOUS GRILL SUPPORTED WITHIN SAID CHAMBER, SO AS TO LIMIT RADIAL EXTENSION OF SAID VANES DURING ROTATION ACROSS SAID INLET PORT AND ACROSS SAID EXHAUST PORT. 